Am 11.04.2013 um 10:02 hat Stefan Hajnoczi geschrieben: > On Wed, Apr 10, 2013 at 07:03:39AM -0700, Josh Durgin wrote: > > On 04/02/2013 07:10 AM, Kevin Wolf wrote: > > >Am 29.03.2013 um 21:03 hat Josh Durgin geschrieben: > > >>The existing bdrv_co_flush_to_disk implementation uses rbd_flush(), > > >>which is sychronous and causes the main qemu thread to block until it > > >>is complete. This results in unresponsiveness and extra latency for > > >>the guest. > > >> > > >>Fix this by using an asynchronous version of flush. This was added to > > >>librbd with a special #define to indicate its presence, since it will > > >>be backported to stable versions. Thus, there is no need to check the > > >>version of librbd. > > > > > >librbd is linked dynamically and the version on the build host isn't > > >necessarily the same as the version qemu is run with. So shouldn't this > > >better be a runtime check? > > > > While we discuss runtime loading separately, would you mind taking this > > patch as-is for now? > > Hi Josh, > I'm happy with Patch v3 1/2. Does that work for you?
Only patch 1/2 would add dead code as .bdrv_aio_flush would never be called. I think we should rather take v1 of the series then, with the #ifdefs at build time. Kevin